Hollow Fiber Dialyzers For Removing Cryoprotective Agents:Theoretical Studies

Removing cryoprotective agents from frozen-thawed blood safely and quickly is always the key point of research. In this manuscript, three different modes are proposed to remove cryoprotective agents (CPAs) from frozen-thawed blood.Firstly, one dilution-concentration mode is introduced. In this model, the effects of the total blood volume, blood hematocrit, blood flow rate, diluent flow rate and diluent region length on cell volume, cell viability and washing time are studied, respectively. The results show that increase the blood flow rate or decrease the diluent flow rate can reduce the osmotic damages to cells; however, only increase the diluent flow rate can reduce the washing time. Thus a big diluent flow rate is recommended in practice. Considering the influences of blood hematocrit, lower is better. Moreover, the total blood volume can also affect the cell viability, but can be solved by extending the length of dilution region.Secondly, the hybrid pre-and post-dilution mode is presented based on the first model. The results show that there is an optimal diluent partition to reduce the maximum cell volume, and different concentration diluent can significantly increase the cell viability.Lastly, a new dynamic dilution-concentration mode is proposed. The effects of blood flow rate, diluent flow rate, the initial volume of hypertonic diluent and the initial concentration of hypertonic diluent are discovered. The results indicate that the increase of diluent flow rate can greatly reduce the washing time while affects little on the cell volume; the blood flow rate, the initial hypotonic diluent volume and concentration can reduce the washing time slightly, but the latter two may prolong the washing time instead while its value is big. Increase the volume and concentration of hypertonic diluent can mitigate the hypotonic damages, but intensify the hypertonic damages.Weighting the three modes proposed above, it is distinctly the last mode is best. This new dynamic dilution model is highly recommended in practice to washing CPAs under maintaining the cell viability.